This invention relates to a waveform synthesizer arrangement for use in various audible output devices.
Generally, in the case where digital information signals which are to be eventually converted into an analog form are derived in a sequence of time, noise in a resulting synthesized waveform varies in nature according to the physical density of digitally encoded data and resolution of quantized values.
While noise can be actually reduced by increasing sampling frequency and the amount of quantized bits, this is disadvantageous due to an increase in the number of data to be treated.
The inventors have recognized that a synthesized waveform with a minimum generation of noise may be easily recoverable when a given process is executed on the data to be reproduced with a consideration of the total nature of the waveform of interest. Since respective values of the data subject to a time sequential process are affected by previous data and have the effect on the frequency construction of resulting waveforms in conjunction with the relative position of the data, it has been found that it is possible to minimize noise harsh to the human's ear by carrying out the time sequential process to exhibit some filtering effect.